She wore a brown floral dress for the ceremony. He wore his U.S. Army uniform, and after all this time, he still worries that it looked too rumpled to pass muster.

When Flo Swanson married Herm Dorion at Fort Lewis, Wash., in July 1942, the future of the world was uncertain — but they were convinced their future meant building a life together. Seven decades later, it turns out they were right.

“We’ve had a wonderful life,” said Herm Dorion, 94, who like his wife is a musician and retired educator. The couple live at the Atria El Camino Gardens senior community in Carmichael, Calif.

“I wouldn’t have had another person,” said Flo Dorion, 92. “We’ve had ups and downs, but we’ve been in love the whole time.”

While the Dorions have had an extraordinarily long marriage, it’s not unusual these days for older couples to celebrate 40, 50 or 60 years together. But in the future, marriages of similar duration will likely be rare.

These days, wedding bells are not ringing — at least, not as often as they used to. As a result, marriage in America has evolved. But into what?

For the Dorions’ generation, marriage was a bedrock of stability, the foundation of family life.

“That was the most unusual generation of the 20th century,” said Andrew Cherlin, a sociology professor at Johns Hopkins University. “They grew up in the Depression and the war. Afterward, the American economy was very strong. People were ready to turn toward home and family.

“The effect of growing up in hard times made them more likely to want a stable family life. That’s one reason we see so many long anniversaries now.”

In contrast, the demographic portrait of marriage today shows the upending of tradition.

Only half of American adults are now married, a record low, compared with 78 percent in 1950. While the divorce rate has leveled off, the marriage rate continues to drop: In 2010, 6.8 people per 1,000 entered new marriages, U.S. Census data shows, compared with 16.4 per 1,000 in 1946, at war’s end.

And couples today are waiting longer to marry. The national average age of people marrying for the first time is 26.5 for brides and 28.7 for grooms. Researchers suggest the average ages are even higher in urban areas.

Statistically speaking, marriage has become the province of the high-achieving: Two-thirds of adults with college degrees get married, compared with less than half of people with only high school diplomas, the Pew Research Center reported. And people without college degrees are more likely to divorce.

“The people who can get good jobs are marrying and staying together,” Cherlin said. “Those are the college-educated people. Marriage is reflecting the socioeconomic polarization in society.”

More than 60 percent of couples today live together before marriage — or instead of marriage, as they churn from one partner to the next through the years — and 41 percent of children are born to single parents.

“More people don’t feel able to afford being married, both financially and socially,” said Todd Migliaccio, a Sacramento State associate sociology professor. “They see marriage as something to do when they’re more stable.

“They don’t want to fail at it. They don’t want to become a statistic.”

Economic forces have always driven marriage trends. During the early Depression years, the marriage rate languished at 7.9 per 1000 — but after World War II, when jobs were plentiful, marriage boomed.

“We look at the 1950s as a golden age of marriage, but it was a statistical anomaly,” said Migliaccio. “It was a blip. A one-income family wage was possible for more families at all class levels.

“Economically as a country, we never had that before, and we never will again.”

And the meaning of marriage in the post-war era was different: It was a sign of adulthood, a first step into a life of responsibility. Less starry-eyed than practical, couples tended not to think of finding their soul mates but rather establishing their stability.

“You got married, got a good job, bought a house and had children,” said Skip Burzumato, assistant director of the National Marriage Project at the University of Virginia.

“Now marriage is maybe third or fourth on the list. It’s no longer the signal to society that you’ve grown up. If you marry too young, parents and society tell you that you’re being irresponsible by not getting those other things lined up.”

Only one-fifth of adults below age 30 are married today, compared with almost 60 percent in 1960, according to census data. The sexual revolution, the result of safe and reliable birth control, clearly played a part in that, researchers say.

“If you were to stand up in front of a crowd of undergraduates today and say, ‘A few decades ago, your age group thought sex, having kids and marriage were inextricably linked,’ they wouldn’t believe it,” said Burzumato.

“They’d think it was the 1500s you’re talking about, not the 1940s or ’50s.”

When they met in 1938 at Modesto Junior College, where they were both music majors, Herm Dorion was a little shy with Flo Swanson, a baker’s daughter from Turlock, Calif. They were in the college orchestra together, then French class.

“I was afraid to talk to her,” Dorion said.

But all these years later, their conversation continues. They still play music together. They raised two daughters and now have three grandchildren. They retired on the same day in 1976 and then traveled the country together in an Airstream.

“Their secret is always doing things together,” said their older daughter, Dianne Dunning, 68. “They love supporting each other no matter what the other one is doing. They’re always side by side.”

Now their walkers are lined up side by side near their recliners in the living room of their comfortable apartment, which is filled with family photos.